At the start of one of these videos, the presenter mentions skipping through some tutorials and agreement pages. He might want to nip back and read those pages because we assume that posting these long and interesting videos is in breach of a non-disclosure agreement. We wouldn’t know, we’re not in the public beta ourselves.
Anyway, the first video shows off some of the creation and customisation of the game before some long gameplay sections. Have a look quick, they might get taken down soon.
The second video shows more gameplay and some different tracks.
Source: via NeoGAF